A fuel supply device for an internal combustion engine includes delivery pipes for storing fuel that is fed under pressure by a fuel pump and supplies fuel by controlling opening of a fuel injection valve connected to each delivery pipe. In the internal combustion engine, since fuel is injected intermittently from the fuel injection valve, the pressure of the fuel is unavoidably pulsated inside the delivery pipes while the injection of the fuel is alternately executed and stopped. This pulsation of the fuel pressure would lead to various kinds of disadvantages such as occurrence of noises or degradation in efficiency of pumping fuel by the fuel pump.
For this reason, as with a fuel supply device disclosed in Japanese Patent No. 2534493, most of the conventional fuel supply devices are provided with a pulsation damper in a fuel passageway through which fuel is fed under pressure to each fuel injection valve, thereby preventing the pulsation of fuel pressure. The device disclosed in Japanese Patent No. 2534493 is provided with one pulsation damper for two delivery pipes connected in series.
In the device disclosed in Japanese Patent No. 2534493, fuel pressure pulsations caused inside each of the delivery pipes interfere with each other before they reach and are then suppressed by the pulsation damper. Such interference of pressure pulses would cause complicated variations in the amplitude and frequency of the pressure pulses, thereby making it extremely difficult to precisely suppress them by means of one pulsation damper.
Provision of separate pulsation dampers, one for each of the two delivery pipes, would make it possible to prevent the fuel pressure from being pulsated in each delivery pipe while preventing the interference between the pressure pulses. However, such one additional pulsation damper would undesirably add the costs of the overall device as well as results in increase in its size for installation.